Optical router for a light-based communication network

ABSTRACT

A point-to-multipoint bi-directional wide area telecommunications network employing atmospheric optical communication. The network comprises a primary transceiver unit, a plurality of subscriber transceiver units and an optical router. The primary transceiver unit may send data destined for the subscriber transceiver units through the optical router, and the subscriber transceiver units may send data destined for the primary transceiver unit through the optical router. The primary transceiver unit and optical router communicate by means of light beams which are transmitted through the atmosphere. Similarly, the optical router and the subscriber transceiver units communicate by means of light beams which are transmitted through the atmosphere.

CONTINUATION DATA

This application is a continuation of co-pending U.S. patent applicationSer. No. 09/106,826 now U.S. Pat. No. 6,348,986 filed on Jun. 29, 1998entitled “Wireless Fiber-Coupled Telecommunication Systems Based onAtmospheric Transmission of Laser Signals” which is acontinuation-in-part of U.S. patent application Ser. No. 08/625,725filed on Mar. 29, 1996 entitled “Point-to-Multipoint Wide AreaTelecommunications Network via Atmospheric Laser Transmission Through aRemote Optical Router” which has issued as U.S. Pat. No. 5,786,923.

FIELD OF THE INVENTION

The present invention relates generally to wireless telecommunicationsnetworks, and more particularly to a broadband telecommunication systemand network which employs atmospheric (i.e. free-space) lasertransmission.

DESCRIPTION OF THE RELATED ART

Broadband communications applications such as interactive television,video telephony, video conferencing, video messaging, video on demand,high definition television (HDTV) and high-speed data services require abroadband communications network between and to the various subscribers.The current telecommunications network, referred to as the PublicSwitched Telephone Network (PSTN) or the plain old telephone system(POTS), is presently the only wired network that is accessible to almostthe entire population. This system, although ideally suited and designedfor point-to-point transmission and any-to-any connectivity, has becomenearly overloaded with the use of voice, fax and data communications.

The PSTN today primarily comprises digital switching systems, andtransmission over the local loop is typically by either T1 feedercopper-based systems or fiber optic cable systems. However, thesubscriber loop is still primarily copper unshielded twisted pair (UTP)wiring, which has a limited capacity. Therefore, the physical nature ofthe system is severely bandwidth limited, with data transmissionstypically in the 9,600-28,800 bits per second range. Thus, high speedbroadband applications cannot feasibly be based on POTS technology.

New hard-wired systems, such as ISDN (Integrated Services DigitalNetwork) and fiber optic networks, offer high speed bi-directionalcommunications available to many individuals. However, ISDN itself maynot provide sufficient bandwidth for many broadband communicationsapplications. In addition, ISDN requires that most subscribers beconnected with upgraded copper wire. A fiber based network, such asfiber to the curb (FTTC) and fiber to the home (FTTH), requires that newfiber optic cable be run to every subscriber. The cost of implementing afiber optic network across the United States would be very expensive.Other alternatives for increasing the capacity of existing networksinclude ADSL (Asymmetric Digital Subscriber Line), SDSL (SymmetricDigital Subscriber Line), and HFC (Hybrid Fiber Coax), among others.

An alternative to hard wired network solutions is a wireless-basedsolution. Most currently existing methods for wirelesstelecommunications are based upon broadcast methodology in theelectromagnetic spectrum. One example of a wireless broadcast medium isthe Direct Broadcast Satellite (DBS) system, such as “DirecTV”. Ingeneral, broadcast systems are widespread and numerous. However,available bandwidth is increasingly limited by the sheer volume ofsubscribers, especially with the rapid growth in the cellular phonemarket. The result of this “crowding of the bands” is that the wirelesselectromagnetic systems are unable to meet the voracious need of thepublic for high speed data communications.

Another method for broadband point-to-point communications employslasers in a point-to-point system that establishes a single continuous,high-speed, bi-directional, multi-channel, atmospheric connection. Laserbased wireless systems have been developed for establishingpoint-to-point, bi-directional and high speed telecommunications throughthe atmosphere. The range for such systems is typically 0.5 to 1.2miles, with some having a range of 4 miles or more. The longestatmospheric communications path achieved with a point-to-point systemexceeded 100 miles. These single path systems require a laser andtransceiver optics at each end of the connection. The connections arecapable of maintaining high speed bi-directional communications in someof the most severe inclement weather conditions. The cost of suchsystems are typically in the $10,000 to $20,000 dollar range however,making them unsuitable for most home and business use.

Therefore, a wireless, laser based telecommunications system is desiredthat enables a number of subscribers to share a communications path to agreat number of subscribers. A wireless, laser based telecommunicationssystem is further desired which reduces the cost to each subscriber, yetstill provides high speed, bi-directional, broadband, wide areatelecommunications. A system is desired which does not require hugeinstallation costs of ISDN and fiber optics, and which does not requireany of the electromagnetic broadcast bands of the mobile communicationsystems. Such a network could be employed in a wide variety ofapplications such as telephony, data communications such as theInternet, teleconferencing, radio broadcast, and various televisionapplications such as cable television, HDTV and interactive TV.

SUMMARY OF THE INVENTION

The present invention comprises a point-to-multipoint bi-directionalwide area telecommunications network employing atmospheric opticalcommunication. The network comprises a primary transceiver unit, anoptical router, and a plurality of subscriber transceiver units. Theprimary transceiver unit generates a first light beam which includesfirst modulated data. The optical router receives the first light beamand demodulates the first data. The optical router modulates the firstdata onto a second light beam and transmits the second light beam to thesubscriber transceiver units. The optical router demodulates, modulatesand transmits to each of the subscriber transceiver units in atime-multiplexed fashion.

The subscriber transceiver units receive the second light beam anddemodulate the first data. Each subscriber transceiver unit comprises anoptical antenna or other optical receiver/transmitter. The opticalantenna is preferably coupled to an input/output device such as aset-top box or display system, e.g., a computer or television, by afiber optic cable.

In the other direction, the subscriber transceiver units atmosphericallytransmit a third light beam which includes second modulated data to theoptical router. The optical router demodulates the second data,modulates the second data on a fourth light beam, and transmits thefourth light beam to the primary transceiver unit. The primarytransceiver unit receives and demodulates the second data. The opticalrouter demodulates, modulates and transmits to each of the subscribertransceiver units in a time-multiplexed fashion. Thereby, bi-directionalcommunication channels between the primary transceiver unit and theplurality of subscriber transceiver units are established fortransferring data in each direction.

The preferred embodiment of the optical router comprises a secondarytransceiver unit, a plurality of transceiver modules and an electronicrouter for routing data between the secondary transceiver unit and theplurality of transceiver modules to establish the communication channelsbetween the primary transceiver unit and the plurality of subscribertransceiver units. The secondary transceiver unit transceives lightbeams including data with the primary transceiver unit and thetransceiver modules transceives light beams including data with thesubscriber transceiver units. The transceiver modules comprise an X-Ybeam deflector for deflecting the light beams to a portion of thesubscriber transceiver units in a time-multiplexed fashion.

In an alternate embodiment of the optical router, the optical routersimply redirects the light beams between the primary transceiver unitand the subscriber transceiver units in a time-multiplexed fashionrather than demodulating and re-modulating the data. The alternateoptical router employs a mirror and lens set to redirect the lightbeams.

Therefore, the present invention comprises a laser-based atmosphericcommunication network which provides broadband bi-directionalcommunications to a plurality of subscribers. The present inventionprovides a bi-directional broadband optical communication network withsignificantly reduced infrastructure costs. A network of such networkscomprising multiple optical routers and multiple primary transceiverunits is further contemplated by the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained when thefollowing detailed description of the preferred embodiment is consideredin conjunction with the following drawings, in which:

FIG. 1 illustrates a point-to-multipoint wide-area telecommunicationsnetwork using atmospheric laser transmission according to the presentinvention;

FIG. 2 illustrates the overlapping coverage achieved by theincorporation of multiple optical routers in the network of FIG. 1;

FIG. 3 illustrates a point-to-multipoint wide area telecommunicationsnetwork using atmospheric laser transmission according to an alternateembodiment of the present invention;

FIG. 4 illustrates the preferred embodiment of the optical router in thenetwork of FIG. 1;

FIG. 5 is a plan view of one of the transceiver modules of FIG. 4;

FIG. 6 is a block diagram of the optical router of FIG. 4, including adetailed block diagram of the secondary transceiver unit;

FIG. 7 illustrates the optical router in the network of FIG. 3;

FIG. 8 illustrates the primary transceiver unit of FIGS. 1 and 3;

FIG. 9 illustrates a subscriber transceiver unit of FIGS. 1 and 3; and

FIG. 10 is a block diagram of a portion of an alternate embodiment ofthe subscriber transceiver unit of FIG. 9.

DETAILED DESCRIPTION OF THE PRESENT INVENTION Incorporation by Reference

U.S. patent application Ser. No. 09/106,826 filed on Jun. 29, 1998entitled “Wireless Fiber-Coupled Telecommunication Systems Based onAtmospheric Transmission of Laser Signals” is hereby incorporated byreference in its entirety.

U.S. patent application Ser. No. 08/625,725 filed on Mar. 29, 1996entitled “Point-to-Multipoint Wide Area Telecommunications Network viaAtmospheric Laser Transmission Through a Remote Optical Router” whichhas issued as U.S. Pat. No. 5,786,923 is hereby incorporated byreference in its entirety.

For general information on broadband telecommunications and optical datacommunications, please see Lee, Kang and Lee, BroadbandTelecommunications Technology, Artech House, 1993 which is herebyincorporated by reference in its entirety. Also please see Davis,Carome, Weik, Ezekiel, and Einzig, Fiber Optic Sensor TechnologyHandbook, Optical Technologies Incorporated, 1982, 1986, Herndon, Va.,which is hereby incorporated by reference in its entirety.

A Network with an Optical Router and a Primary Transceiver

Referring now to FIG. 1, a point-to-multipoint wide-areatelecommunications network 3100 using atmospheric light beam or lasertransmission according to the present invention is shown. The network3100 preferably comprises a primary transceiver unit 3120, an opticalrouter 3110 and a plurality of subscriber transceiver units 3130A-3130N(referred to collectively as 3130). In an alternate embodiment, thenetwork 3100 comprises only the optical router 3110 and the plurality ofsubscriber transceiver units. The present invention provides a broadbandbi-directional communication network with reduced infrastructure costs,i.e., no cable or fiber is required to be laid in the subscriber loop,i.e., to the subscribers.

According to the preferred embodiment of network 3100, the subscribertransceiver units are located at subscriber premises, such as homes orbusinesses. The optical router 3110 is located in the vicinity of thesubscriber transceiver units 3130, and the optical router opticallycommunicates with the subscriber units 3130. The optical router 3110 hasan associated range of accessibility, wherein the optical router 3110 iscapable of communicating with subscriber transceiver units locatedwithin a circular area around the optical router 3110. In the preferredembodiment of optical router 3110, the range of accessibility isapproximately between 2000 and 4000 feet. It is contemplated, however,that optical router 3110 may be configured with larger or smaller rangesof accessibility. Each of the subscriber transceiver units 3130 ispositioned in a line of sight path relative to the optical router 3110.

The optical router 3110 is positioned in a line of sight path relativeto the primary transceiver unit 3120. The optical router 3110 ispreferably mounted on, for example, a pole, building, or other structureapproximately 75 feet above ground level. Preferably the distancebetween the primary transceiver unit 3120 and the optical router 3110 isapproximately in the range from one half to ten miles. It iscontemplated, however, that larger or smaller distances may existbetween the optical router 3110 and the primary transceiver unit 3120 ofnetwork 3100

The primary transceiver unit 3120 generates a first light beam 3140 andatmospherically transmits the first light beam 3140 to the opticalrouter 3110. In the preferred embodiment, the term “light beam” isintended to encompass any of various types of light transmission,including lasers, a super-fluorescent light source, or other coherentand/or non-coherent light or optical transmission.

The primary transceiver unit 3120 modulates data on the first light beam3140 before transmitting the first light beam 3140 to the optical router3110. Data may be modulated on the first light beam using any of varioustechniques, including amplitude and/or frequency modulation techniques,as is well known in the art.

The optical router 3110 atmospherically receives the first light beam3140 including the data sent by the primary transceiver unit 3120 anddemodulates the data, then modulates the data on and atmosphericallytransmits a second light beam 3845A-3845N (referred to collectively as3845) to the subscriber transceiver units 3130. The second light beam3845 contains at least a portion of the data sent by the primarytransceiver unit 120. The subscriber transceiver units 3130atmospherically receive the second light beam 3845 and demodulate thedata sent by the primary transceiver unit 3120 from the second lightbeam 3845. The present invention distinguishes among different users,i.e., shares the communication bandwidth, using techniques such astime-division multiple access (TDMA) or frequency-division multipleaccess (FDMA). The present invention may also use code-division multipleaccess (CDMA) techniques.

The subscriber transceiver units 3130 atmospherically transmit a thirdlight beam 3855A-3855N (referred to collectively as 3855) to the opticalrouter 3110. The subscriber transceiver units 3130 modulate data on thethird light beam 3855 and then transmit the third light beam 3855 to theoptical router 3110. The optical router 3110 atmospherically receivesthe third light beam 3855 including the data sent by the subscribertransceiver units 3130 and demodulates the data, then modulates the dataon and atmospherically transmits a fourth light beam 3150 to the primarytransceiver unit 3120. The primary transceiver unit 3120 receives thefourth light beam 3150 and demodulates the data sent by the subscribertransceiver units 3130 from the fourth light beam 3150.

The optical router 3110 routes data between the primary transceiver unit3120 and each of the subscriber transceiver units 3130 thus establishingchannels of communication, that is, subscriber channels, on the lightbeams between the primary transceiver unit 3120 and the subscribertransceiver units 3130. Preferably the optical router 3110 establishessubscriber channels in a time-multiplexed fashion. During a firsttime-period the optical router 3110 establishes a first set of one ormore subscriber channels between the primary transceiver unit 3120 and afirst set of one or more subscriber transceiver units 3130. Next, theoptical router 3110 establishes a second set of subscriber channelsbetween the primary transceiver unit 3120 and a second set of subscribertransceiver units 3130 during a second time-period. The optical router3110 proceeds in this manner, establishing a two-way or bi-directionalsubscriber channel with each of the subscriber transceiver units 3130 inthe range of accessibility of the optical router 3110.

One embodiment of network 3100 contemplates any or all of the firstlight beam 3140, second light beam 3845, third light beam 3855, andfourth light beam 3150, comprising a plurality of different wavelengths,wherein data is modulated on each wavelength of the light beams, therebyadvantageously increasing the bandwidth of the subscriber channels.

The network of the present invention may support a large number ofsubscribers. One embodiment contemplates on the order of 1000 subscribertransceiver units supported by a single optical router.

In an alternative embodiment of network 3100, primary transceiver unit3120 receives the first light beam 3140 from another transceiver (notshown) and optically redirects the first light beam 3140 to opticalrouter 3110. Conversely, primary transceiver 3120 optically redirectsthe fourth light beam 3150 from optical router 3110 to the othertransceiver.

In a second alternative embodiment of network 3100, primary transceiverunit 3120 receives a source light beam from another transceiver (notshown), and demodulates data from the source light beam which thenbecomes the data source for modulating the first light beam. Conversely,primary transceiver unit 3120 demodulates data sent by the subscribertransceiver units from the fourth light beam 3150. The demodulated datais modulated onto a return light beam which is atmosphericallytransmitted to the other transceiver.

In a third alternative embodiment of network 3100, optical router 3110communicates with another transceiver (not shown). Optical router 3110atmospherically transmits the fourth light beam 3150 to the othertransceiver for demodulation, and receives the first light beam 3140from the other transceiver.

Thus, it may be readily observed that the elements recited above form awireless point-to-multipoint wide-area telecommunications network. Byestablishing subscriber communications channels in a multiplexed mannerusing atmospherically transmitted light beams, the present inventionadvantageously provides a telecommunications network which has thepotential to be much less expensive than current wired networks whichrely on copper wire and/or optical fiber.

Additionally, the present invention advantageously provides a much lessexpensive telecommunications network than a network which employs anarray of point-to-point atmospherically transmitted light beams.

Further, by employing light beams as the communications path, thepresent invention advantageously avoids the costs associated withlicensing and purchasing bands in the radio spectrum.

Finally, the present invention advantageously provides a communicationsnetwork which consumes much less power than a system which employs anangularly dispersed light beam.

In the preferred embodiment of network 3100, the primary transceiverunit 3120 communicates control information to the optical router 3110and subscriber transceiver units 3130. The control information for theoptical router 3110 contains information about the angular location ofthe subscriber transceiver units 3130. The control information alsocontains timing information to instruct the optical router 3110regarding multiplexing of the light beams and thus establishing thesubscriber communications channels. The control information for thesubscriber transceiver units 3130 contains timing informationinstructing the subscriber transceiver units 3130 about when to transmitthe third light beam 3855 to the optical router 3110. The primarytransceiver unit 3120 transmits the first light beam 3140 and receivesthe fourth light beam 3150 cooperatively according to the controlinformation which the primary transceiver unit 3120 communicates to theoptical router 3110 and subscriber transceiver units 3130.

In the preferred embodiment of network 3100, the primary transceiverunit 3120 includes a master clock and computes timing controlinformation based upon at least a plurality of the following factors:the data packet size, the local speed of light, the number ofsubscribers, the distance between the primary transceiver unit and theoptical router, the distance between the optical router and therespective subscriber transceiver unit, the processing time of thesubscriber transceiver units, the time associated with the electronicrouter (discussed below), and the switching speed of the X-Y beamdeflectors (discussed below).

In the preferred embodiment of network 3100, the first light beam 3140and the fourth light beam 3150 are substantially collinear as are thesecond light beam 3845 and third light beam 3855. The collinear lightbeam embodiment advantageously allows many of the optical components ofthe primary transceiver unit, optical router and subscriber transceiverunits to be shared by the light beams. In this embodiment, the firstlight beam 3140 and the fourth light beam 3150 have differentfrequencies or polarities as do the second light beam 3845 and thirdlight beam 3855 to advantageously avoid cross-talk between the two lightbeams. In an alternate embodiment, the first light beam 3140 and fourthlight beam 3150 are in close proximity but not collinear as are thesecond light beam 3845 and third light beam 3855.

Referring now to FIG. 2, a network comprising a plurality of opticalrouters is shown. Each optical router has an associated range ofaccessibility. In one embodiment of the present invention, the opticalrouters are spatially located such that the accessibility ranges of someof the optical routers overlap. That is, more than one optical router isable to service a given subscriber. FIG. 2 shows various regions ofcoverage and indicates the number of optical routers which may service asubscriber located in the region.

In one embodiment of network 3100, if a subscriber transceiver unitdetects a loss of reception of the first light beam, the subscribertransceiver unit searches for another optical router by which to receiveservice. By providing overlapping coverage of a given subscriber bymultiple optical routers, the present invention advantageously providesan element of redundancy and hence more reliable operation.

In FIG. 2, three optical routers are shown. However, the presentinvention is not limited in the number of optical routers which may beserviced by a given primary transceiver unit 3120, nor the number ofoptical routers which may service a given subscriber transceiver unit3130.

In one embodiment of network 3100, the primary transceiver unit 3120comprises a plurality of light sources to generate a plurality of firstlight beams to transmit to a plurality of optical routers. In anotherembodiment of network 3100, the primary transceiver unit 3120 comprisesa single light source to generate a single light beam, and the primarytransceiver unit 3120 is configured to split the light beam generated bythe single light source into multiple first light beams which aretransmitted to a plurality of optical routers. In both embodiments theprimary transceiver unit 3120 modulates subscriber data on each firstlight beams.

Alternate Embodiments

Referring now to FIG. 3, an alternate embodiment of the network 3100 ofFIG. 1 is shown. The embodiment of FIG. 3 is similar to the embodimentof FIG. 1, and corresponding elements are numbered identically forsimplicity and clarity. The optical router 3110 of FIG. 3 corresponds tothe alternate embodiment of the optical router 3110 shown in FIG. 7 anddescribed below. In the alternate embodiment the optical router 3110redirects the light beam from the primary transceiver unit 3120 to thesubscriber transceiver units 3130 and redirects the light beams from thesubscriber transceiver units 3130 to the primary transceiver unit 3120rather than demodulating the data and re-modulating it. The opticalrouter 3110 receives the first light beam 3140 and redirects the firstlight beam 3140 to the subscriber transceiver units 3130. The subscribertransceiver units 3130 receive the first light beam 3140 and demodulatethe data sent by the primary transceiver unit 3120 from the first lightbeam 3140. The present embodiment distinguishes among different users,i.e., shares the communication bandwidth, using techniques such as timedivision multiple access (TDMA) or frequency division multiple access(FDMA). The present embodiment may also use code division multipleaccess (CDMA) techniques.

The subscriber transceiver units 3130 atmospherically transmit a secondlight beam 3150A-3150N (referred to collectively as 3150) to the opticalrouter 3110. The subscriber transceiver units 3130 modulate data on thesecond light beam 3150 and then transmit the second light beam 3150 tothe optical router 3110. The optical router 3110 receives the secondlight beam 3150 and redirects the second light beam 3150 to the primarytransceiver unit 3120. The primary transceiver unit 3120 receives thesecond light beam 3150 and demodulates the data sent by the subscribertransceiver units 3130 from the second light beam 3150. Alternatively,the optical router 3110 and/or the primary transceiver unit 3120 providethe second light beam 3150 to another transceiver (not shown) fordemodulation, wherein this other transceiver is in communication withthe primary transceiver unit 3120.

The optical router 3110 redirects the first and second light beamsbetween the primary transceiver unit 3120 and each of the subscribertransceiver units 3130 during different time periods, that is, in atime-multiplexed manner. In other words, the optical router 3110establishes channels of communication comprising the light beams betweenthe primary transceiver unit 3120 and the subscriber transceiver units3130 in distinct time slices. Thus, during a first time period theoptical router 3110 establishes a first subscriber channel byredirecting the first light beam 3140 from the primary transceiver unit3120 to a first subscriber transceiver unit 3130 and redirecting thesecond light beam 3150 from the first subscriber transceiver unit 3130to the primary transceiver unit 3120. Next, the optical router 3110establishes a second subscriber channel between the primary transceiverunit 3120 and a second subscriber transceiver unit 3130 during a secondtime period. The optical router 3110 proceeds in this manner,establishing a two-way or bi-directional subscriber channel with each ofthe subscriber transceiver units 3130 in the range of accessibility ofthe optical router 3110.

An alternate embodiment of the network 3100 contemplates an alternatemultiplexing scheme wherein the primary transceiver unit 3120 isconfigured to generate and/or transmit a first light beam 3140 whichcomprises a plurality of different wavelengths which correspond to thesubscribers. The optical router 3110 receives the first light beam andprovides each of the wavelength portions to the respective subscribertransceiver units. In this embodiment, the optical router 3110 includesa grating, such as a diffraction grating, which separates the differentfrequency or spectra and provides the different wavelength portions tothe respective subscribers. Additionally, each subscriber transceiverunit is configured to generate a second light beam of one or morerespective unique wavelengths. The optical router 3110 redirects therespective wavelength light beams of the first and second light beamsbetween the primary transceiver unit 3120 and respective subscribertransceiver units 3130, that is, in a frequency-multiplexed manner.Alternately stated, the optical router 3110 establishes subscriberchannels of communication on the light beams between the primarytransceiver unit 3120 and the subscriber transceiver units 3130 basedupon different wavelength portions of a light beam. Thus, the opticalrouter 3110 establishes a first subscriber channel by redirecting afirst wavelength portion of the first light beam from the primarytransceiver unit 3120 to a first subscriber transceiver unit 3130 andredirecting the second light beam 3150 comprising the first wavelengthfrom the first subscriber transceiver unit 3130 to the primarytransceiver unit 3120. Simultaneously, the optical router 3110establishes a second subscriber channel between the primary transceiverunit 3120 and a second subscriber transceiver unit 3130 using a secondwavelength portion of the first light beam 3140 and a second light beam3150 comprising the second wavelength. The optical router 3110 operatesin this manner, establishing a subscriber channel with subscribertransceiver units 3130 in the range of accessibility of the opticalrouter 3110. By employing multiple wavelength light beams and FDMAtechniques, the invention advantageously increases the bandwidthavailable to the subscribers.

Another alternate multiplexing embodiment is contemplated in which theoptical router 3110 establishes subscriber communication channels in acombined time-multiplexed and frequency-multiplexed manner. A subscriberrequiring increased data bandwidth employs a subscriber transceiver unitconfigured to receive multiple light beams of differing wavelengthsand/or multiple time-slots, thereby multiplying the bandwidth availableto the subscriber. In another embodiment, the present invention employscode division multiple access (CDMA) techniques using bipolar codes.

The present invention contemplates an alternate embodiment of thenetwork 3100 comprising unidirectional data transmission, that is,broadcast or point-to-multipoint data communication only from theprimary transceiver unit 3120 and/or optical router 3110 to thesubscriber transceiver units 3130. In this embodiment, the subscribertransceiver units 3130 do not generate light beams back through theoptical router 3110 to the primary transceiver unit 3120. Other aspectsof this alternate embodiment are as described above in the preferredembodiment of FIG. 1 and the alternate embodiment of FIG. 3. Thisalternate embodiment is contemplated as an advantageous alternative tocurrent implementations of broadcast television, particularly highdefinition television, or cable television, for example. Thus thisembodiment may comprise a pure broadcast (one-way) network.Alternatively, the network 3100 may use a different return path from thesubscriber units 3130 to the primary transceiver unit 3120, such as ananalog modem (POTS) or ISDN.

The present invention further contemplates an alternate embodiment ofthe network 3100 in which the primary transceiver unit 3120 essentiallyresides in the same location as the optical router 3110. Alternatelystated, the primary transceiver unit 3120 and the optical router 3110are essentially combined into a single unit. In this embodiment thelight source of the primary transceiver unit 3120 transmits only a fewinches or feet into the optical router 3110. Various elements of theprimary transceiver unit 3120 and optical router 3110 may be eliminatedor combined in such an embodiment. In this embodiment, fiber optic cablemay be used to transfer the light beam directly to the optical router3110, and thus a separate primary transceiver unit 3120 is not needed.

The Optical Router

Referring now to FIG. 4, the preferred embodiment of the optical router3110 in the network 3100 (of FIG. 1) is shown. The optical router 3110comprises a secondary transceiver unit 3700 coupled to a plurality oftransceiver modules 3800A-3800M (referred to collectively as 3800) by anelectronic router 3790. The transceiver modules 3800 are coupled to acircular backplane 3889. The electronic router 3790 is coupled to thetransceiver modules 3800 through the backplane 3889.

Transceiver module 3800A (representative of the transceiver modules3800) has a backplane connector 3888 which connects the transceivermodule 3800A to the backplane. The transceiver module 3800A isconfigured to transmit the second light beam 3845 to and receive thethird light beam 3855 from a portion of the subscriber transceiver units3130, namely those subscriber transceiver units 3130 within a portion ofthe circular area around the optical router 3110. The transceivermodules 3800 collectively provide the optical router 3110 with a 360degree range of accessibility to the subscriber transceiver units 3130.

A beam deflector control system 3795 is coupled through the backplane3889 to the transceiver modules 3800 for controlling the deflection ofthe second light beam 3845 and third light beam 3855 by the transceivermodules 3800. The beam deflector control system 3795 is also coupled tothe electronic router 3790 and receives beam deflector controlinformation from the primary transceiver unit 3120 through theelectronic router 3790.

The electronic router 3790 receives routing control information from theprimary transceiver unit 3120. The routing control information regardsthe routing of data sent by the primary transceiver unit 3120 from thesecondary transceiver unit 3700 to the various transceiver modules 3800for atmospheric transmission to the subscriber transceiver units 3130.Conversely, the routing control information regards the routing of datasent by the subscriber transceiver units 3130 from the varioustransceiver modules 3800 to the secondary transceiver unit 700 foratmospheric transmission to the primary transceiver unit 3120.

The secondary transceiver unit 3700 atmospherically receives the firstlight beam 3140 including the data sent by the primary transceiver unit3120 and demodulates the data. The secondary transceiver unit 3700communicates the data sent by the primary transceiver unit 3120 to theelectronic router 3790. The electronic router 3790 routes the data fromthe secondary transceiver unit 3700 to the appropriate one of thetransceiver modules 3800. For illustration purposes let us assumetransceiver module 3800A is the appropriate transceiver module 3800. Thetransceiver module 3800A receives the data and modulates the data ontothe second light beam 3845 which is atmospherically transmitted to theappropriate subscriber transceiver unit 3130A.

Conversely, the transceiver module 3800A receives the third light beam3855 including data from the subscriber transceiver unit 3130 anddemodulates the data. The transceiver module 3800A communicates the datasent by the subscriber transceiver unit 3130A to the electronic router3790. The electronic router 3790 routes the data from the transceivermodule 3800A to the secondary transceiver unit 3700. The secondarytransceiver unit 700 modulates the data sent by the subscribertransceiver unit 3130A onto the fourth light beam 3150 andatmospherically transmits the fourth light beam 3150 including the datasent by the subscriber transceiver unit 3130A to the primary transceiverunit 3120.

FIG. 5

Referring now to FIG. 5, a plan view of the transceiver module 3800A ofthe optical router 3110 of FIG. 4 is shown. The transceiver module 3800Acomprises a light source 3862 configured to generate the second lightbeam 3845. A beam modulator 3864 receives data which was sent by theprimary transceiver unit 3120 from the electronic router 3790 throughthe backplane connector 3888 and modulates the data onto the secondlight beam 3845. The second light beam 3845 is deflected by an X-Y beamdeflector 3840 to the subscriber transceiver unit 3130A.

Preferably the X-Y beam deflector 3840 is a galvanometer mirror pair.Galvanometer mirrors are well known, particularly in the art of laserprinter technology and the art of laser light shows. Alternatively theX-Y beam deflector 3840 is an acousto-optic or solid state beamdeflector. The optical router 3110 light source 3862 preferablycomprises one or more continuous wave or pulsed beam lasers as are wellknown in the art, such as gas, solid state or diode lasers. The beammodulator 3864 preferably comprises an electro-optic cell.Alternatively, the beam modulator 3864 is a bulk type modulator. Thelight source and beam modulator configuration is indicative of thosewell known in fiber optic communication link transmission systems.However, the laser power output is typically significantly greater thanthose used in fiber optic systems.

While the X-Y beam deflector 3840 deflects the second light beam 3845 tothe subscriber transceiver unit 3130A the X-Y beam deflector 3840simultaneously deflects the third light beam 3855 from the subscribertransceiver unit 3130A to a beam splitter 3880. The beam splitter 3880splits a relatively large portion of the third light beam 3855 to a beamdemodulator 3872 which receives the third light beam 3855 anddemodulates data sent by the subscriber transceiver unit 3130A from thethird light beam 3855. The beam demodulator 3872 communicates the datathrough the backplane connector 3888 to the electronic router 3790. Thebeam demodulator 3872 preferably comprises a photo-diode as is common inthe art.

During a first time period, the X-Y beam deflector 3840 deflects thesecond light beam 3845 from the light source 3862 to a first subscribertransceiver unit 3130A and deflects the third light beam 3855 from thefirst subscriber transceiver unit 3130A to the beam demodulator 3872.Hence, the transceiver module 3800A establishes a bi-directionalcommunications channel using the second and third light beams betweenthe transceiver module 3800A and the first subscriber transceiver unit3130A for a first period of time. Hence, the bi-directionalcommunications channel between the transceiver module 3800A and thefirst subscriber transceiver unit 3130A comprises a portion of thesubscriber channel described above between the primary transceiver unit3120 and the subscriber transceiver unit 3130A. During subsequentperiods of time the X-Y beam deflector 3840 deflects the second andthird light beams to and from other subscriber transceiver units 3130 ina time-multiplexed manner.

Each of the transceiver modules 3800 establishes bi-directionalcommunication channels as just described between the given transceivermodule and the portion of the subscriber transceiver units 3130accessible by the given transceiver module in a time-multiplexed fashionand simultaneously with the other transceiver modules. In this manner, aportion of a wireless point-to-multipoint bi-directional wide areatelecommunications network is advantageously formed between the opticalrouter 3110 and the subscriber transceiver units 3130.

The beam splitter 3880 splits a relatively small portion of the thirdlight beam 3855 to a beam alignment detector 3852 which receives thesplit portion of the third light beam 3855 and detects misalignment orwander of the third light beam 3855 from the subscriber transceiver unit3130A which may occur and stores the beam stabilization information. Thebeam alignment detector 3852 communicates the beam stabilizationinformation through the backplane 888 via the electronic router 3790 tothe secondary transceiver unit 3700. The secondary transceiver unit 3700transmits the beam stabilization information to the primary transceiverunit 3120. The primary transceiver unit 3120 communicates the beamstabilization information to the given subscriber transceiver unit sothat the subscriber transceiver unit can adjust the beam formisalignment or wander appropriately. Atmospheric turbulence and densityvariations along the atmospheric path between the subscriber transceiverunit 3130A and the optical router 3110 may account for misalignment ofthe third light beam 3855 on the X-Y beam deflector 3840 of thetransceiver module 3800A. Likewise, events such as ground shifting ortower sway may cause the positions of the subscriber transceiver unit3130A or optical router 3110 relative to each other to change.

FIG. 6

Referring now to FIG. 6, a block diagram of the optical router 3110 ofFIG. 4 is shown including a detailed block diagram of the secondarytransceiver unit 3700. A transceiver module 300A is coupled to theelectronic router 3790 through the backplane 3889. The electronic router3790 is also coupled to the other transceiver modules 3800 (not shown).The electronic router 3790 is coupled to the beam deflector controlsystem 3795 and to the secondary transceiver unit 3700.

The secondary transceiver unit 3700 comprises an optical antenna 3210which receives the first light beam 3140 from the primary transceiverunit 3120. The optical antenna 3210 also transmits the fourth light beam3150 to the primary transceiver unit 3120. The optical antenna 3210preferably comprises an optical system with a conic mirror, which iswell known in the art. Alternatively the optical antenna 3210 is acollecting lens system which is also well known in the art. The opticalantenna 3210 and associated optics converge and re-collimate theincoming first light beam 3140 to a relatively small diameter,preferably in the range of 1 to 3 millimeters. Conversely, the opticalantenna 3210 receives a relatively small diameter fourth light beam 3150generated by a light source 3362 and expands and re-collimates thefourth light beam 3150 for atmospheric transmission to the primarytransceiver unit 3120.

The optical antenna 3210 atmospherically receives the first light beam3140 including the data sent by the primary transceiver unit 3120 (ofFIG. 1) from the primary transceiver unit 3120 and directs the firstlight beam 3140 to a beam demodulator 3372. The beam demodulator 3372demodulates the data sent by the primary transceiver unit 3120 from thefirst light beam 3140 and communicates the data to the electronic router3790. The data sent by the primary transceiver unit 3120 comprisessubscriber data as well as control data. The control data comprisesrouting control information for the electronic router 3790 as well astiming control information and angular position control information ofthe subscriber transceiver units 3130 for the beam deflector controlsystem 3795. The electronic router 3790 uses the routing controlinformation to route the subscriber data to the appropriate transceivermodules 3800. The electronic router 3790 communicates the timing controlinformation and the angular position control information to the beamdeflector control system 3795. The beam demodulator 3372 preferablycomprises a photo-diode as is common in the art.

The light source 3362 generates the fourth light beam 3150. Theelectronic router 3790 routes the data sent by the subscribertransceiver units 3130 from the transceiver modules 3800 to a beammodulator 3364. The beam modulator 3364 modulates the data sent by thesubscriber transceiver units 3130 onto the fourth light beam 3150 fortransmission to the optical antenna 3210 and on to the primarytransceiver unit 3120.

The light source 3362 preferably comprises one or more continuous waveor pulsed beam lasers as are well known in the art, such as gas, solidstate or diode lasers. The beam modulator 3364 preferably comprises anelectro-optic cell. Alternatively, the beam modulator 3364 is a bulktype modulator. The light source and beam modulator configuration isindicative of those well known in fiber optic communication linktransmission systems. However, the laser power output is typicallysignificantly greater than those used in fiber optic systems.

As the first light beam 3140 passes from the optical antenna 3210 to thebeam demodulator 3372 the first light beam 3140 is directed toward thebeam demodulator 3372 by a beam separator 3380. Conversely, as thefourth light beam 3150 passes from the light source 3362 to the opticalantenna 3210 the fourth light beam 3150 passes through the beamseparator 3380.

The X-Y beam deflector 3840 is coupled through the backplane 3889 to thebeam deflector control system 3795. The beam deflector control system3795 controls the switching of the X-Y beam deflector 3840 to deflectthe second light beam 3845 and third light beam 3855 to and from thedesired subscriber transceiver unit 3130 at the desired time. Thus in atime-multiplexed fashion the beam deflector control system controls theestablishing of the portion of the subscriber channels between thesubscriber transceiver units 3130 and the transceiver modules 3800.

Preferably, the beam deflector control system 3795 receives controlinformation from the primary transceiver unit 3120 to control the X-Ybeam deflector 3840. The control information for the beam deflectorcontrol system 3795 contains information about the angular location ofthe subscriber transceiver units 3130. The beam deflector control system3795 uses the subscriber transceiver unit angular location informationto determine the desired deflection angles of the X-Y beam deflector3840.

As mentioned in the discussion of FIG. 1, the primary transceiver unit3120 also preferably transmits multiplexing control information to theoptical router 3110 and to the subscriber transceiver units 3130. Theprimary transceiver unit 3120 transmits the control information for oneor more subscriber channels prior to transmitting the subscriber datapackets associated with the one or more subscriber channels. Themultiplexing information is timing information used by the beamdeflector control system 3795 to control the X-Y beam deflector 3840regarding when to deflect the second and third light beams to and from agiven subscriber transceiver unit 3130.

The subscriber transceiver unit transmits the third light beam 3855containing data for the primary transceiver unit 3120 to the opticalrouter 3110 at a time determined by the primary transceiver unit 3120.Correspondingly, the transceiver module servicing the subscribertransceiver unit transmits the second light beam with the data modulatedfor the subscriber transceiver unit to arrive at the X-Y beam deflectorat substantially the same time as the third light beam 3855 containingdata from the first subscriber arrives at the optical router 3110. Theprimary transceiver unit 3120 transmits the first light beam 3140containing data for the subscriber transceiver unit to arrive at theoptical router 3110 at a time such that the data may be demodulated,routed, modulated on the second light beam 3845 and the second lightbeam 3845 transmitted to arrive at the X-Y beam deflector 3840 atsubstantially the same time as the third light beam 3855 containing datafrom the first subscriber arrives at the optical router 3110.

By employing optical components to converge and re-collimate the lightbeams as described previously, the internal components of the opticalrouter 3110, such as the beam deflector, advantageously operate onrelatively narrow light beams. This improves the accuracy of beamredirection. Conversely, by employing optical components to expand andre-collimate the light beams as described previously, the light beamstraveling through the atmosphere between network elements areadvantageously relatively wide light beams. This improves the receptioncharacteristics of the light beams as they are received by the networkcomponents.

The optical router 3110 further comprises an active optics controlsystem 3350, such as are well known, particularly in the defenseindustry. The active optics control system 3350 provides stabilizationof the first light beam 3140 on the optical antenna 3210 of the opticalrouter 3110 and of the fourth light beam 3150 on the optical antenna3710 (of FIG. 8) of the primary transceiver unit 3120. As the firstlight beam 3140 travels from the optical antenna 3210 toward the beamdemodulator 3372, a small portion of the first light beam 3140 is splitby a beam separator 3380 and redirected to a beam alignment detector3352. The beam alignment detector 3352 detects misalignment or wander inthe first light beam 3140 which may occur and stores the beamstabilization information. Atmospheric turbulence and density variationsalong the atmospheric path between the primary transceiver unit 3120 andthe optical router 3110 may account for misalignment of the first lightbeam 3140 on the optical router 3110. Likewise, events such as groundshifting or tower sway may cause the positions of the primarytransceiver unit 3120 or optical router 3110 relative to each other tochange.

The active optics control system 3350 communicates the beamstabilization information to the electronic router 3790 which in turncommunicates the beam stabilization information to the beam modulator3364. The beam modulator 3364 modulates the beam stabilizationinformation data onto the fourth light beam 3150 during a designatedtime period for atmospheric transmission to the primary transceiver unit3120. The primary transceiver unit 3120 demodulates the beamstabilization information data from the fourth light beam 3150 and usesthe beam stabilization information to make corrections and stabilize thefirst light beam 3140 on the optical router 3110.

Additionally, the active optics control system 3350 uses the beammisalignment information to control a beam adjuster 3220, positionedbetween the optical antenna 3210 and the beam splitter 3230, to adjustthe first light beam 3140 optimally into the beam demodulator 3372.

As previously mentioned the primary transceiver unit 3120 communicatescontrol information to the optical router 3110. The control informationfurther comprises beam stabilization information. The active opticscontrol system 3350 uses the beam stabilization information from theprimary transceiver unit 3120 to control the optical antenna 3210 andbeam adjuster 3220 to make corrections and stabilize the fourth lightbeam 3150 on the primary transceiver unit 3120.

Preferably the beam separator 3380 is a dichroic mirror. Alternatively,the first light beam 3140 and fourth light beam 3150 are orthogonallypolarized and the beam separator 3380 is a polarization separator.

In the preferred embodiment of the invention, the optical router 3110periodically polls the subscriber transceiver units 3130 by allocating acommunication channel to each of the subscriber transceiver units 3130within the range of accessibility of the optical router 3110. However,the optical router 3110 may lose reception of the third light beam 3855from a given subscriber transceiver unit for a significant period oftime. The most common cause of the reception loss is the subscribertransceiver unit being powered off. When the optical router 3110 detectsreception loss, the optical router 3110 preferably and advantageouslypolls the powered-off subscriber less frequently than subscribertransceiver units which are actively transmitting a third light beam3855 to the optical router 3110.

Alternate Embodiment

Referring now to FIG. 7, an alternate embodiment of the optical router3110 in the network 3100 (of FIG. 3) is shown. The optical router 3110comprises an optical antenna 3210 which receives the first light beam3140 from the primary transceiver unit 3120. The optical antenna 3210also transmits the second light beam 3150 received from a subscribertransceiver unit to the primary transceiver unit 3120. The opticalantenna 3210 preferably comprises an optical system with a conic mirror,which is well known in the art. In an alternate embodiment the opticalantenna 3210 is a collecting lens system which is also well known in theart. The optical antenna 3210 and associated optics converge andre-collimate the incoming first light beam 3140 to a relatively smalldiameter, preferably in the range of 1 to 3 millimeters. Conversely, theoptical antenna 3210 receives a relatively small diameter second lightbeam 3150 received from internal components of the optical router 3110and expands and re-collimates the second light beam 3150 for atmospherictransmission to the primary transceiver unit 3120.

The optical antenna 3210 receives the first light beam 3140 from theprimary transceiver unit 3120 (of FIG. 3) and directs the first lightbeam 3140 to an X-Y beam deflector 3240. The beam deflector 3240receives the first light beam 3140 and deflects the first light beam3140 toward a mirror 3261. The mirror 3261 reflects the first light beam3140 to a respective one or more of the subscriber transceiver units3130 (of FIG. 3). Conversely, the subscriber transceiver units 3130transmit respective second light beams 3150 to the mirror 3261. Themirror 3261 reflects a received second light beam 3150 to the beamdeflector 3240. The beam deflector 3240 deflects the second light beam3150 to the optical antenna 3210. The optical antenna 3210 receives thesecond light beam 3150 and transmits the second light beam 3150 to theprimary transceiver unit 3120.

Preferably, during a first time period, the beam deflector 3240 deflectsthe first light beam 3140 from the optical antenna 3210 to a location onthe mirror 3261 and deflects the second light beam 3150 fromsubstantially the same location on the mirror to the optical antenna3210. The location on the mirror 3261 is calculated to reflect the firstlight beam 3140 to a particular subscriber transceiver unit and reflectthe second light beam 3150 from the particular subscriber transceiverunit. Hence, the optical router 3110 establishes a bi-directionalcommunications channel using the first and second light beams betweenthe primary transceiver unit 3120 and one of the subscriber transceiverunits 3130 for a period of time. During subsequent periods of time thebeam deflector 3240 deflects the light beams to other locations on themirror 3261 in order to establish channels with the other subscribertransceiver units 3130 serviced by the optical router 3110. In thismanner, a wireless point-to-multipoint bi-directional wide areatelecommunications network is advantageously formed.

The beam deflector 3240 is controlled by a beam deflector control system3340 coupled to the beam deflector 3240. The beam deflector controlsystem 3340 controls the beam deflector 3240 to deflect the light beamsto the desired locations on the mirror 3261 during the desired time.Preferably, the beam deflector control system 3340 receives controlinformation from the primary transceiver unit 3120 to control the beamdeflector 3240. The control information for the optical router 3110contains information about the angular location of the subscribertransceiver units 3130. The beam deflector control system 3340 uses thesubscriber transceiver unit angular location information to determinethe desired locations on the mirror 3261 used for deflection of thelight beams.

As mentioned in the discussion of FIG. 3, the primary transceiver unit3120 also preferably transmits multiplexing control information to theoptical router 3110 and to the subscriber transceiver units 3130. Theprimary transceiver unit 3120 transmits the control information for oneor more subscriber channels prior to transmitting the subscriber datapackets associated with the one or more subscriber channels. Preferably,the multiplexing information is timing information used by the beamdeflector control system 3340 to control the beam deflector 3240regarding when to deflect the light beams to and from a particularlocation on the mirror 3261. A first subscriber transceiver unit 3130transmits the second light beam 3150 containing data for the primarytransceiver unit 3120 to the optical router 3110 at a time determined bythe primary transceiver unit 3120. Correspondingly, the primarytransceiver unit 3120 transmits the first light beam 3140 containingdata for the first subscriber to the optical router 3110 at a time suchthat the first light beam 3140 containing data for the first subscriberarrives at the optical router 3110 at substantially the same time thesecond light beam 3150 containing data from the first subscriber arrivesat the optical router 3110. Additionally, the beam deflector controlsystem 3340 controls the beam deflector 3240 to redirect the first andsecond light beams between the primary transceiver unit 3120 and firstsubscriber transceiver unit 3130 during the time when the first andsecond light beams are passing through the optical router 3110, asdirected by the primary transceiver unit 3120.

Preferably, the X-Y beam deflector 3240 is a galvanometer mirror pair.Galvanometer mirrors are well known, particularly in the art of laserprinter technology and the art of laser light shows.

One embodiment contemplates the beam deflector 3240 comprising aplurality of such galvanometer mirror pairs. Each galvanometer mirrorpair deflects a different light beam between the mirror 3261 and theoptical antenna 3210. The primary transceiver unit 3120 transmits thefirst light beam 3140 which is comprised of multiple light beams each ofa different wavelength, i.e., the first light beam 3140 includes aplurality of different wavelengths. The optical router 3110 splits thefirst light beam 3140 into respective wavelength portions which aredeflected by respective beam deflectors. Conversely, multiple subscribertransceiver units 3130 transmit second light beams 3150 of differingwavelengths which arrive simultaneously at the optical router 3110. Theoptical router 3110 combines the multiple wavelength second light beams3150 and transmits the multiple wavelength second light beam 3150 to theprimary transceiver unit 3120.

Other embodiments contemplate the beam deflector 3240 comprising one ormore acousto-optic or solid state beam deflectors.

Preferably the mirror 3261 is a conical or hemispherical mirror whereinthe cone axis is in a vertical orientation, thus providing 360 degreeaccess to subscribers with an elevation aperture covering the accessarea to a range of approximately between 2000 and 4000 feet. The mirror3261 is circumscribed by a lens set 3262. The lens set 3262 preferablycomprises a plurality of relatively small positive lenses arrayed in aconical or hemispherical fashion. As the relatively small diameter firstlight beam 3140 reflects from the mirror 3261, the first light beam 3140expands in diameter. The lens set 3262 re-collimates the expanding firstlight beam 3140 back to a slightly converging first light beam 3140 foratmospheric transmission to the subscriber transceiver units 3130.Conversely, the lens set 3262 focuses the second light beam 3150 fromthe subscriber transceiver units 3130 onto the mirror 3261. An apertureis formed in the lens set 3262 through which the relatively smalldiameter first and second light beams travel between the X-Y beamdeflector 3240 and the mirror 3261. The mirror 3261 and lens set 3262collimate beam 3150 in a manner optimized for the optical router 3261access area.

By employing optical components to converge and re-collimate the lightbeams as described previously, the internal components of the opticalrouter 3110, such as the beam deflector, advantageously operate onrelatively narrow light beams. This improves the accuracy of beamredirection. Conversely, by employing optical components to expand andre-collimate the light beams as described previously, the light beamstraveling through the atmosphere between network elements areadvantageously relatively wide light beams. This improves the receptioncharacteristics of the light beams as they are received by the receiversof the network components.

The optical router 3110 further comprises a receiver 3370 and a beamseparator 3380. Preferably, the optical router 3110 establishes acontrol channel between the primary transceiver unit 3120 and theoptical router 3110 for use in communicating control information, aspreviously discussed, from the primary transceiver unit 3120 to theoptical router 3110. The control channel is distinct from the subscriberchannels. Preferably, the beam deflector control system 3340 controlsthe beam deflector 3240 to redirect a particular first light beam 3140to the beam separator 3380 rather than to the subscriber transceiverunits 3130. This redirection to the beam separator 3380 rather than tothe subscriber units 3130 preferably occurs at preset periods of time.The beam separator 3380 redirects the particular first light beam 3140to the receiver 3370, which receives the first light beam 3140. Theprimary transceiver unit 3120 correspondingly modulates the controlinformation data on the first light beam 3140 to be received anddemodulated by the beam demodulator 3372 in the receiver 3370. Thereceiver 3370 is coupled to the beam deflector control system 3340 andcommunicates the control information data to the beam deflector controlsystem 3340. The beam demodulator 3372 preferably comprises aphoto-diode as is common in the art.

Preferably, the control channel is established in a time-multiplexedmanner. During a time period, which is distinct from time periodsdevoted to subscriber channels, the beam control system 3340 controlsthe beam deflector 3240 to deflect the first light beam 3140 to alocation on the mirror 3261 such that the first light beam 3140 isreflected to the beam separator 3380 rather than to the subscribertransceiver units 3130. The primary transceiver unit 3120 instructs theoptical router 3110 to establish this control channel prior to the timefor the optical router 3110 to establish the control channel.Preferably, during initialization, the optical router 3110 devotes allcommunication channels to be control channels until instructed by theprimary transceiver unit 3120 to allocate subscriber channels.

In an alternate embodiment, the control channel is established in afrequency-multiplexed manner wherein a light beam of a distinctfrequency, which is distinct from frequencies devoted to subscriberchannels, is devoted to control channels.

The optical router 3110 further comprises an active optics controlsystem 3350, such as are well known, particularly in the defenseindustry. The active optics control system 3350 provides stabilizationof the first light beam 3140 on the optical antenna 3210 of the opticalrouter 3110 and the second light beam 3150 on the optical antenna 3710(of FIG. 8) of the primary transceiver unit 3120. As the first lightbeam 3140 travels from the optical antenna 3210 to the beam deflector3240, a small portion of the first light beam 3140 is split by a beamsplitter 3230 and redirected to a beam alignment detector 3352. The beamalignment detector 3352 detects misalignment or wander in the firstlight beam 3140 which may occur and stores the beam stabilizationinformation. Atmospheric turbulence and density variations along theatmospheric path between the primary transceiver unit 3120 and theoptical 3110 may account for misalignment of the first light beam 3140on the optical router 3110. Likewise, events such as ground shifting ortower sway may cause the positions of the primary transceiver unit 3120or optical router 3110 relative to each other to change.

The active optics control system 3350 communicates the beamstabilization information to the primary transceiver unit 3120 on acontrol channel. The primary transceiver unit 3120 uses the beamstabilization information to make corrections and stabilize the firstlight beam 3140 on the optical router 3110.

The optical router 3110 further comprises a transmitter 3360 including alight source 3362 and a beam modulator 3364. The active optics controlsystem 3350 provides the beam stabilization information of the firstlight beam 3140 to the transmitter 3360. The light source 3362 generatesand atmospherically transmits a control light beam 3250. The beammodulator 3364 modulates the positional information on the control lightbeam 3250 as it travels through the beam separator 3380 to the mirror3261. Thus a control channel is established between the optical router3110 and the primary transceiver unit 3120, similar to the controlchannel described above in which the primary transceiver unit 3120transmits control information to the optical router 3110, but in theopposite direction. That is, while the beam deflector 3240 is controlledto deflect the first light beam 3140 to the mirror 3261 such that themirror 3261 reflects the first light beam 3140 to the receiver 3370, thebeam deflector 3240 also deflects the control light beam 3250 from themirror 3261 to the optical antenna 3210. This provides a two-way orbi-directional control channel.

The optical router 3110 light source 3362 preferably comprises one ormore continuous wave or pulsed beam lasers as are well known in the art,such as gas, solid state or diode lasers. The beam modulator 3364preferably comprises an electro-optic cell. Alternatively, the beammodulator 3364 is a bulk type modulator. The light source and beammodulator configuration is indicative of those well known in fiber opticcommunication link transmission systems. However, the laser power outputis typically significantly greater than those used in fiber opticsystems.

Additionally, the active optics control system 3350 uses the beammisalignment information to control the beam adjuster 3220 to adjust thefirst light beam 3140 optimally into the beam deflector 3240.

As previously mentioned the primary transceiver unit 3120 communicatescontrol information to the optical router 3110. The control informationfurther comprises beam stabilization information which the opticalrouter 3110 receives on the control channels. The active optics controlsystem 3350 of the optical router 3110 uses the beam stabilizationinformation from the primary transceiver unit 3120 to control theoptical antenna 3210 and beam adjuster 3220 to make corrections andstabilize the second light beam 3150 on the primary transceiver unit3120.

In an alternate embodiment, the optical router active optics controlsystem 3350 further comprises a second beam alignment detector (notshown) which detects misalignment or wander in the second light beam3150 from the subscriber transceiver units 3130 and stores the beamstabilization information. The optical router 3110 communicates the beamstabilization information to the primary transceiver unit 3120. Theprimary transceiver unit 3120 in turn communicates the beamstabilization information to the subscriber transceiver units 3130. Theactive optics control systems in the subscriber transceiver units 3130,discussed below, use the beam stabilization information from the primarytransceiver unit 3120 to control the subscriber transceiver unit opticalantennas and beam adjusters to make corrections for misalignment orwander and stabilize the second light beam 3150 on the optical router3110.

In one embodiment the beam separator 3380 is a dichroic mirror. Inanother embodiment, the first light beam 3140 and second light beam 3150are orthogonally polarized and the beam separator 3380 is a polarizationseparator.

Preferably, the optical router 3110 periodically polls the subscribertransceiver units 3130 by allocating a communication channel to each ofthe subscriber transceiver units 3130 within the range of accessibilityof the optical router 3110. However, the optical router 3110 may losereception of the second light beam 3150 from a given subscribertransceiver unit for a significant period of time. The most common causeof the reception loss is the subscriber transceiver unit being poweredoff. When the optical router 3110 detects reception loss, the opticalrouter 3110 preferably and advantageously polls the powered-offsubscriber less frequently than subscriber transceiver units which areactively transmitting a second light beam 3150 to the optical router3110.

The Primary Transceiver Unit

Referring now to FIG. 8, the preferred embodiment of the primarytransceiver unit 3120 in the network 3100 (of FIG. 1) is shown. Theprimary transceiver unit 3120 comprises an optical antenna 3710optically coupled to a transmitter 3750 and a receiver 3770.

The optical antenna 3710 transmits the first light beam 3140 to theoptical router 3110 (of FIG. 1) and receives the fourth light beam 3150from the optical router 3110. (It is noted that for the network 3100where the alternate embodiment of the optical router 3110 is employed,i.e., the network of FIG. 3, the optical antenna 3710 receives thesecond light beam 3150.) The optical antenna 3710 preferably is similarto the optical antenna 3210 of the optical router 3110. An opticalantenna 3710 of the primary transceiver unit 3120 is contemplated withdifferent dimensions and optical characteristics than the opticalantenna 3210 of the optical router 3110.

The optical antenna 3710 of the primary transceiver unit 3120 ispreferably larger than the subscriber transceiver unit optical antenna.Preferably, the receiver 3770 of the primary transceiver unit 3120 ismore sensitive, i.e., able to demodulate a weaker light beam, than thatof the subscriber transceiver units. Thus the subscriber transceiverunit light source, discussed below, may be less powerful, thus reducingthe cost of the subscriber transceiver units. In other words, theprimary transceiver unit 3120 transmitter light source 3754 ispreferably more powerful than the subscriber transceiver unit lightsource. This allows the subscriber transceiver unit antenna, discussedbelow, to be relatively small and the subscriber transceiver unitreceiver, discussed below, to be relatively less sensitive. Hence thetotal cost of the system is reduced since the number of subscribertransceiver units is typically much greater than the number of primarytransceiver units in the network.

A data source/sink (not shown) provides data to the primary transceiverunit 3120 to be sent to the subscriber transceiver units 3130. The datasource/sink ties into and/or uses existing communication structures suchas a telephone network, cable television system, the Internet or othernetworks employing Asynchronous Transfer Mode (ATM), switched-ethernet,SONNET, FDDI, Fibre-Channel, Serial Digital Heirarchy, etc. Variousmeans for coupling the data source/sink to the primary transceiver unit3120 are contemplated, such as fiber-optic cable, satellite up-links anddown-links, atmospheric light beams, coaxial cable, microwave links,etc. The light source 3754 generates and atmospherically transmits thefirst light beam 3140 upon which the beam modulator 3752 modulates thedata to be sent to the subscriber transceiver units 3130. A beamadjuster 3720, which preferably comprises an adjustable fine steeringmirror, receives and reflects the first light beam 3140 to a lensassembly 3780 and optical antenna 3710 which expand, re-collimate andtransmit the first light beam 3140 to the optical router 3110.

Conversely, the primary transceiver unit optical antenna 3710atmospherically receives the fourth light beam 3150 from the opticalrouter 3110, and the lens assembly 3780 focuses the fourth light beam3150 onto the beam adjuster 3720. The beam adjuster 3720 reflects thenarrowed fourth light beam 3150 to a beam separator 3740. The beamseparator 3740 is similar to that of the optical router 3110. The beamseparator 3740 redirects the fourth light beam 3150 to the receiver3770. The beam demodulator 3772 receives the fourth light beam 3150 anddemodulates the data sent by the subscriber transceiver units 3130. Thedata is then provided to the data source/sink. The beam demodulator 3772preferably comprises a photo-diode, as is common in the art.

The primary transceiver unit light source 3754 preferably comprises oneor more continuous wave or pulsed beam lasers as are well known in theart, such as gas, solid state or diode lasers. The beam modulator 3752preferably comprises an electro-optic cell. Alternatively, the beammodulator 3752 is a bulk type modulator. The light source and beammodulator configuration is similar to those well known in fiber opticcommunication link transmission systems. However, the laser power outputis typically significantly greater than those used in fiber opticsystems.

The light beam wavelengths generated by the atmospherically transmittinglight sources described in the present invention are chosen to minimizethe power loss through the atmosphere. Preferably the wavelengths are inthe near infrared range.

The lens assembly 3780 and optical antenna 3710 are configured totransmit the first light beam 3140 having a beam waist which isadvantageously located at the optical router 3110. The diameter of thefirst light beam 3140 leaving the optical antenna 3710 is many times thediameter of the first light beam 3140 exiting the light source 3754.Thus the laser power density is spread over a relatively large,cross-sectional area, which enhances eye-safety. Additionally, therelatively large diameter of the light beams traveling between thecomponents of the network improves the reception characteristics of thelight beams at the optical receivers.

The primary transceiver unit 3120 additionally comprises a controlsystem (not shown) which computes the previously discussed routing, beamstabilization, timing, subscriber location and multiplexing controlinformation.

The primary transceiver unit 3120 further comprises an active opticscontrol system 3760 similar to the active optics control system 3350 ofthe optical router 3110. The primary transceiver unit active opticscontrol system 3760 cooperates with the optical router active opticscontrol system 3350 to provide stabilization of the first light beam3140 on the optical antenna 3210 of the optical router 3110 and thefourth light beam 3150 on the optical antenna 3710 of the primarytransceiver unit 3120.

As previously mentioned, the optical router 3110 communicates beamstabilization information to the primary transceiver unit 3120. Theactive optics control system 3760 uses the beam stabilizationinformation from the optical router 3110 to control the optical antenna3710 and beam adjuster 3720 to make corrections and stabilize the firstlight beam 3140 on the optical router 3110.

Additionally, the active optics control system 3760 uses the beammisalignment information detected by the beam alignment detector 3762 tocontrol the beam adjuster 3720 to adjust the fourth light beam 3150optimally into the receiver 3770.

The Subscriber Transceiver Units

Referring now to FIG. 9, an illustration of the preferred embodiment ofa subscriber transceiver unit 3130A in the network 3100 (of FIG. 1) isshown. Subscriber transceiver unit 3130A is representative of theplurality of subscriber transceiver units 3130. The subscribertransceiver unit 3130A comprises an optical antenna 3510 coupled to aninput/output device 3600, such as a set-top box 3600, by a fiber opticcable 3590. The input/output device 3600 may be any of various devices,including a set-top box, computer system, television, radio,teleconferencing equipment, telephone or others which may be coupled tothe optical antenna 3510 by a fiber optic cable 3590. In the remainderof this disclosure, the input/output device 3600 is referred to as a settop box. Power and control wires (not shown) also couple the subscriberoptical antenna 3510 and the set-top box 3600.

The optical antenna 3510 receives the second light beam 3845 from theoptical router 3110 (of FIG. 1) and transmits the third light beam 3855to the optical router 3110. (It is noted that for the network 3100 wherethe alternate embodiment of the optical router 3110 is employed, i.e.,the network of FIG. 3, the subscriber transceiver unit 3130A receivesthe first light beam 3140 from the optical router 3110 and transmits thesecond light beam 3150 to the optical router 3110.) The optical antenna3510 preferably is similar to the optical antenna 3210 of the opticalrouter 3110. An optical antenna 3510 of the subscriber transceiver unit3130A is contemplated with different dimensions and opticalcharacteristics than the optical antenna 3210 of the optical router3110.

The optical antenna 3510 receives the second light beam 3845 and focusesthe second light beam 3845 into a fiber-optic coupling 3580. Thefiber-optic coupling 3580 couples the second light beam 3845 into thefiber optic cable 3590. The fiber optic cable 3590 carries the secondlight beam 3845 to the set-top box 3600. A beam separator 3570 in theset-top box 3600 redirects the second light beam 3845 to a receiver 3550which receives the second light beam 3845. A beam demodulator 3552 inthe receiver 3550 demodulates the data from the second light beam 3845.The receiver 3550 provides the data to external connections (not shown)on the set-top box 3600, which connect to various devices such astelevisions, computers, radios, teleconferencing equipment andtelephones (also not shown). The beam demodulator 3552 preferablycomprises a photo-diode as is common in the art.

Conversely, the various digital devices provide data to be sent to theprimary transceiver unit 3120 (of FIG. 1) to a transmitter 3560 in theset-top box 3600. The set-top box 3600 comprises a light source 3564which generates the third light beam 3855. A beam modulator 3562 in thetransmitter 3560 modulates the data to be sent to the primarytransceiver unit 3120 on the third light beam 3855. The third light beam3855 passes through the fiber optic cable 3590 to the fiber-opticcoupling 3580. The fiber optic coupling 3580 decouples the third lightbeam 3855 from the fiber optic cable 3590 and atmospherically redirectsthe third light beam 3855 to the optical antenna 3510. The opticalantenna 3510 then transmits the third light beam 3855 including the datato the optical router 3110.

The subscriber transceiver unit 3130A light source 3564 preferablycomprises one or more continuous wave or pulsed beam lasers as are wellknown in the art, such as gas, solid state or diode lasers. The beammodulator 3562 preferably comprises an electro-optic cell.Alternatively, the beam modulator 3562 is a bulk type modulator. Thelight source and beam modulator configuration is similar to those wellknown in fiber optic communication link transmission systems. However,the laser power output is typically greater than those used in fiberoptic systems.

In an alternate embodiment, previously mentioned, the subscribertransceiver unit 3130A is configured to transmit and receive multiplewavelength light beams in order to increase the data bandwidth availableto a given subscriber.

The subscriber transceiver unit 3130A further comprises an active opticscontrol system 3540 similar to the active optics control system of theoptical router 3110 and the primary transceiver unit 3120. Thesubscriber transceiver unit active optics control system 3540 cooperateswith the primary transceiver unit 3120 active optics control system toprovide stabilization of the second light beam 3845 on the subscribertransceiver unit 3130A and the third light beam 3855 on the opticalrouter 3110.

A beam alignment detector 3542 detects misalignment or wander in thesecond light beam 3845 from the optical router 3110 and stores the beamstabilization information. The subscriber transceiver unit 3130Acommunicates the beam stabilization information regarding the firstlight beam 3150 to the primary transceiver unit 3120 via the transmitter3560. The invention contemplates the beam stabilization informationbeing communicated to the primary transceiver unit 3120 in a header in asubscriber data packet. The invention additionally contemplates the beamstabilization information being communicated to the primary transceiverunit 3120 via a dedicated control data packet. The primary transceiverunit 3120 utilizes the beam stabilization information when computingpositional and multiplexing control information.

A beam adjuster 3520 optically positioned between the optical antenna3510 and the fiber optic coupling 3580 is controlled by the activeoptics control system 3540 to maintain efficient coupling of the secondlight beam 3845 into the fiber optic cable 3590.

The optical antenna 3510 is mounted on gimbals (not shown) which allowthe optical antenna 3510 to rotate and search for an optical router3110, or different transceiver module 3800 of the preferred opticalrouter 3110, by which to receive service upon installation or upon lossof reception from a current optical router 3110 or transceiver module3800.

Alternate Embodiments

An alternate embodiment of the subscriber transceiver unit 3130A iscontemplated in which the light beams are converted to/from electricalsignals at the optical antenna 3510 and transmitted in electronic formto the input/output device 3600. Hence, alternative transmission mediumsfor coupling the optical antenna 3510 to the input/output device 3600are contemplated such as coaxial cable or other forms of electricalwires.

Referring now to FIG. 10, an alternate embodiment of the set-top box3600 of FIG. 9 is shown. A fiber optic “T” 4020 is coupled to the fiberoptic cable 3590. The second light beam 3845 enters the fiber optic “T”4020 and passes along the fiber optic cable 3590 to a beam demodulator4030. The beam demodulator 4030 is similar to and performs similarfunctions to the beam demodulator 3552 of the preferred embodiment. Thesecond light beam 3845 then passes through the fiber optic cable 3590 toan optical data remover 4040. The optical data remover 4040 preferablycomprises a micro-bender. The data remover 4040 removes any data whichhas been modulated on the second light beam 3845. At this point thesecond light beam 3845 essentially becomes the third light beam 3855.The third light beam 3855 is then passed along the fiber optic cable3590 to a beam modulator 4050. The beam modulator 4050 is similar to andperforms similar functions to the beam modulator 3562 of the preferredembodiment of the subscriber transceiver unit 3130A. The third lightbeam 3855 including the second data is then passed to the fiber optic“T” 4020 and on to the fiber optic coupling for transmission to theoptical router 3110. The alternate embodiment advantageously avoids thecost of a light source.

An alternate embodiment of the subscriber transceiver unit 3130A opticalantenna is contemplated in which the antenna is an omni-directionalantenna. The omni-directional antenna is similar to the mirror and lensset assembly of the alternate embodiment of the optical router 3110.Additionally, a beam deflector is provided for coupling and decouplingthe light beams into and out of the fiber optic coupling 3580.Alternatively, the fiber optic coupling 3580 is rotatably mounted. Thealternate embodiment advantageously enables the subscriber unit 3130 toreceive service from an alternate optical router 3110 with minimalinterruption of data transmission. In addition, installation of thesubscriber transceiver unit 3130 is simplified in that virtually noalignment must be performed upon installation, other than achieving aline of sight path to one or more optical routers 3110.

The present invention contemplates the use of fiber optic amplifiers,such as an EDFA (erbium-doped fiber amplifier), in one or more of thevarious network elements for amplifying the various light beams in orderto achieve appropriate signal power levels of the various light beamswithin the network.

The present invention contemplates the use of atomic line filters, whichact as optical band-pass filters for selected light wavelengths, in oneor more of the various network element receivers for filtering outnecessary light wavelengths, such as sunlight.

The present invention contemplates the use of light sources in thevarious network element transmitters with adjustable light beam powercontrol. The light beam power is adjusted according to factors such asweather conditions to achieve a proper fade margin for the signal power.A fade margin of 15 dB at a 1 km range to achieve a 10⁻⁹ bit error rateis preferred.

CONCLUSION

Therefore, the present invention comprises a wirelesspoint-to-multipoint wide area telecommunications network by establishingsubscriber communications channels in a multiplexed manner usingatmospherically transmitted light beams. The network employs an opticalrouter to establish the communications channels between a primarytransceiver unit and a plurality of subscriber transceiver units bytime-multiplexing, light beam frequency multiplexing, or a combinationthereof, the atmospherically transmitted light beams.

Although the systems and networks of the present invention have beendescribed in connection with several preferred embodiments, the presentinvention is not intended to be limited to the specific forms set forthherein, but on the contrary, it is intended to cover such alternatives,modifications, and equivalents, as can be reasonably included within thespirit and scope of the invention as defined by the appended claims.

What is claimed is:
 1. An optical router comprising: an optical antennaconfigured to receive a first light beam comprising first data from theatmosphere; a mirror; and a first X-Y beam deflector opticallypositioned between said optical antenna and said mirror, wherein saidfirst X-Y beam deflector is configured to receive the first light beamfrom the optical antenna and to deflect the first light beam onto one ormore positions on a surface of the mirror; wherein the mirror isconfigured to reflect the first light beam in one or more directionsinto the atmosphere corresponding to the one or more positions on themirror surface.
 2. The optical router of claim 1, wherein the mirror isconfigured to receive one or more second light beams, each comprisingcorresponding second data, from the atmosphere, and to reflect the oneor more second light beams to the first X-Y beam deflector; wherein thefirst X-Y beam deflector is configured to deflect the one or more secondlight beams to the optical antenna; and wherein the optical antenna isconfigured to transmit the one or more second light beams into theatmosphere.
 3. The optical router of claim 1 further comprising a lensset which circumscribes said mirror; wherein said lens set has anaperture which admits passage of the first light beam after deflectionfrom the first X-Y beam deflector and before reflection from saidmirror; and wherein said lens set is configured to re-collimate saidfirst light beam after reflection from said mirror.
 4. The opticalrouter of claim 3, wherein the lens set comprises an array of positivelenses.
 5. The optical router of claim 3, wherein said mirror and saidlens set are optimized for the access area of the optical router.
 6. Theoptical router of claim 2 further comprising a lens set whichcircumscribes said mirror; wherein said lens set has an aperture whichadmits passage of the one or more second light beams after reflectionfrom said mirror and before deflection on said first X-Y beam deflector;and wherein said lens set is further configured to focus the one or moresecond light beams received from the atmosphere onto the mirror.
 7. Theoptical router of claim 2 further comprising a receiver and an activeoptics control system; wherein the first light beam, received by theoptical antenna from the atmosphere, is transmitted into the atmosphereby a primary transceiver unit; wherein the one or more second lightbeams, transmitted by the optical antenna into the atmosphere, arereceived by the primary transceiver unit; wherein the first light beamcomprises a first beam portion which carries beam stabilizationinformation, wherein the beam stabilization information indicatesmisalignment of the one or more second beams on a primary antenna of theprimary transceiver unit; wherein the receiver is configured to receivesaid first beam portion of said first light beam, to demodulate the beamstabilization information from the first beam portion, and to providethe beam stabilization information to the active optics control system;wherein the active optics control system is configured to control theoptical antenna to stabilize the one or more second light beams on theprimary antenna of the primary transceiver unit in response to the beamstabilization information.
 8. The optical router of claim 7 furthercomprising a beam adjuster optically positioned between the opticalantenna and the first X-Y beam deflector; wherein the active opticscontrol system is additionally configured to control the beam adjusterto stabilize the one or more second light beams on the primary antennaof the primary transceiver unit in response to the beam stabilizationinformation.
 9. The optical router of claim 7 wherein the first beamportion is a wavelength component of the first light beam or atime-slice of the first light beam.
 10. The optical router of claim 2further comprising an active optics control system; wherein the one ormore second light beams, received at the mirror from the atmosphere,include a particular light beam transmitted into the atmosphere by afirst subscriber transceiver unit; wherein the active optics controlsystem is configured to receive a portion of the particular light beam,detect misalignment of the particular light beam on the mirror based onsaid portion of the particular light beam, and generate correspondingbeam stabilization information; wherein the beam stabilizationinformation is usable by the first subscriber transceiver unit to adjusta transmission direction of the particular light beam to optimallydirect the particular light beam to the mirror of the optical router.11. The optical router of claim 10 further comprising a beam splitteroptically positioned between the optical antenna and the first X-Y beamdeflector; wherein the mirror and first X-Y beam deflector direct theparticular light beam to the beam splitter; wherein the beam splitter isconfigured to redirect said portion of the particular light beam to theactive optics control system, and to pass a remaining portion of theparticular light beam to the optical antenna.
 12. The optical router ofclaim 10 further comprising a light source and a beam modulator; whereinthe active optics control system is configured to provide the beamstabilization information to the beam modulator; wherein the lightsource is configured to generate a control light beam; wherein the beammodulator is configured to modulate the beam stabilization informationonto the control light beam; wherein the mirror and first X-Y beamdeflector direct the modulated control light beam to the opticalantenna; wherein the optical antenna is configured to transmit themodulated control light beam into the atmosphere to a transceiver sourceof the first light beam.
 13. The optical router of claim 1, wherein thefirst X-Y beam deflector is configured to deflect the first light beamonto a first position of said one or more positions on the mirrorsurface during a first time period, wherein the mirror reflects thefirst light beam in a first direction into the atmosphere based on saidfirst position on said mirror surface; and wherein the first X-Y beamdeflector is configured to deflect the first light beam onto a secondposition of said one or more positions on the mirror surface during asecond time period, wherein the mirror reflects the first light beam ina second direction into the atmosphere based on said second position onsaid mirror surface.
 14. The optical router of claim 13, wherein thefirst position on the mirror surface is selected so that the firstdirection corresponds to a first subscriber transceiver unit; wherein,during the first time period, (a) the mirror receives a third light beamfrom the first subscriber transceiver unit, (b) the X-Y beam deflectordeflects the third light beam to the optical antenna, and (c) theoptical antenna transmits the third light beam to a transceiver sourceof the first light beam.
 15. The optical router of claim 1, wherein themirror is a hemispherical mirror, or a conical mirror.
 16. The opticalrouter of claim 1 further comprising a receiver and a beam deflectorcontrol system; wherein the first X-Y beam deflector is configured todeflect the first light beam onto a third position on the mirror surfaceduring a third time period, wherein the third position is selected sothat the mirror reflects the first light beam onto a optical path whichtargets the receiver, wherein the first light beam carries routingcontrol information during the third time period; wherein the receiveris configured to receive the first light beam, to demodulate the routingcontrol information from the first light beam, and to provide therouting control information to the beam deflector control system; andwherein the beam deflector control system controls the orientation ofthe first X-Y beam deflector in response to the routing controlinformation.
 17. The optical router of claim 16, wherein said beamdeflector control system controls switching times of the first X-Y beamdeflector in response to the routing control information.
 18. Theoptical router of claim 16, wherein the receiver comprises a photodiode.19. The optical router of claim 1, wherein said first light beamcomprises a first wavelength beam component carrying a first portion ofsaid first data and a second wavelength beam component carrying a secondportion of said first data; wherein said optical router furthercomprises a second X-Y beam deflector and a means for separating thefirst and second wavelength components from the first light beam; andwherein the first X-Y beam deflector is configured to receive the firstwavelength component and to deflect the first wavelength component ontoa first position of said one or more positions on the mirror surface sothat the mirror reflects the first wavelength component in a firstdirection into the atmosphere; and wherein the second X-Y beam deflectoris configured to receive the second wavelength component and to deflectthe second wavelength component onto a second position of the mirrorsurface so that the mirror reflects the second wavelength component in asecond direction.
 20. The optical router of claim 19, wherein the firstposition on the mirror surface is selected so that the first directioncorresponds to a first subscriber, wherein the second position on themirror surface is selected so that the second direction corresponds to asecond subscriber.
 21. The optical router of claim 19, wherein the firstX-Y beam deflector and second X-Y beam deflector are configured tosimultaneously deflect the first and second wavelength componentsrespectively.
 22. The optical router of claim 1 further comprising areceiver and a beam deflector control system; wherein the first lightbeam comprises a first beam portion which carries control information;wherein the receiver is configured to receive said first beam portion ofsaid first light beam, to demodulate the control information from thefirst beam portion, and to provide at least a portion of the controlinformation to the beam deflector control system; wherein the beamdeflector control system is configured to control the orientation of thefirst X-Y beam deflector in response to said at least said portion ofthe control information.
 23. The optical router of claim 22, wherein thefirst beam portion of said first light beam comprises a first time-sliceof the first light beam.
 24. The optical router of claim 22, wherein thefirst beam portion of said first light beam comprises a first wavelengthcomponent of the first light beam.
 25. The optical router of claim 1,wherein the first X-Y beam deflector comprises a galvanometer mirrorpair.
 26. The optical router of claim 1, wherein the first X-Y beamdeflector comprises an acousto-optic deflector.
 27. The optical routerof claim 1, wherein the first X-Y beam deflector comprises a solid statebeam deflector.
 28. The optical router of claim 1 further comprising abeam splitter, an active optics beam control system; wherein said beamsplitter is optically positioned between said optical antenna and saidfirst X-Y beam deflector, wherein beam splitter is configured toredirect a first portion of the first light beam to the active opticsbeam control system; wherein the active optics beam control system isconfigured to receive said first portion of the first light beam, detectmisalignment of the first light beam on the optical antenna based onsaid first portion, and generate corresponding first beam stabilizationinformation, wherein the first beam stabilization information is usableby a transceiver source of the first beam to adjust the transmissiondirection of the first beam to minimize the misalignment of the firstlight beam on the optical antenna.
 29. The optical router of claim 28further comprising a light source and a beam modulator; wherein theactive optics control system is further configured to provide the firstbeam stabilization information to the beam modulator; wherein the lightsource is configured to generate a control light beam; wherein the beammodulator is configured to modulate the first beam stabilizationinformation onto the control light beam; wherein the beam modulator isoriented so that the modulated control light beam is directed to a firstposition on the mirror surface; wherein the first position on the mirrorsurface is chosen so that the mirror reflects the modulated controllight beam to the first X-Y beam deflector; wherein the first X-Y beamdeflector is configured to deflect the modulated control light beam tothe optical antenna; wherein the optical antenna is configured totransmit the modulated control light beam into the atmosphere to thetransceiver source of the first light beam.
 30. The optical router ofclaim 28 further comprising beam adjuster optically positioned betweenthe optical antenna and the beam splitter; wherein the active opticscontrol system is configured to control the beam adjuster so that thefirst light beam is optimally directed to the first X-Y beam deflector.31. An optical router comprising: an optical antenna configured toreceive a first light beam comprising a plurality of wavelengthcomponents from the atmosphere, wherein each of said wavelengthcomponents carries corresponding first data; a mirror; and first andsecond X-Y beam deflectors optically positioned between said opticalantenna and said mirror; wherein said first X-Y beam deflector isconfigured to receive a first wavelength component of the first beam andto deflect the first wavelength component onto a first position on asurface of the mirror; wherein said second X-Y beam deflector isconfigured to receive a second wavelength component of the first beamand to deflect the second wavelength component onto a second position onthe mirror surface; wherein the mirror is configured to simultaneously(a) reflect the first wavelength component into the atmosphere in afirst direction corresponding to the first position on the mirrorsurface, and (b) reflect the second wavelength component into theatmosphere in a second direction corresponding to the second position onthe mirror surface.
 32. The optical router of claim 31 furthercomprising a means for splitting the first light beam received from theoptical antenna into said first wavelength component and said secondwavelength component.
 33. The optical router of claim 31, wherein themirror is configured to simultaneously (c) receive a first subscriberlight beam, comprising a third wavelength component, from theatmosphere, and reflect the first subscriber light beam to the first X-Ybeam deflector, and (d) receive a second subscriber light beam,comprising a fourth wavelength component, from the atmosphere, andreflect the second subscriber light beam to the second X-Y beamdeflector; wherein the third wavelength component carries firstsubscriber data, wherein the fourth wavelength component carries secondsubscriber data; wherein the first X-Y beam deflector and second X-Ybeam deflector are configured to deflect the first subscriber light beamand the second subscriber light beam respectively to the opticalantenna; wherein the optical antenna is configured to transmit acombined light beam comprising the first subscriber light beam and thesecond subscriber light beam into the atmosphere.
 34. An optical routercomprising: a secondary transceiver unit configured to receive a firstlight beam comprising first data from the atmosphere, and to demodulatethe first data from the first light beam; one or more transceivermodules, wherein each of said one or more transceiver modules comprisesa module light source, configured to generate a corresponding secondlight beam, a module beam modulator and a module X/Y beam deflector; anelectronic router configured to receive the first data from thesecondary transceiver unit, and to route portions of the first data tothe one or more transceiver modules; wherein the module beam modulatorof a first transceiver module of said one or more transceiver modules isconfigured to receive one or more of said portions of said first datafrom said electronic router, and modulate said one or more portions ontothe corresponding second light beam; wherein the module X/Y beamdeflector of the first transceiver module is configured to receive themodulated second light beam and to deflect the modulated second lightbeam into the atmosphere in one or more spatial directions.
 35. Theoptical router of claim 34, wherein said one or more portions of saidfirst data comprise a first portion and a second portion; wherein,during a first time period, (a) the module beam modulator of the firsttransceiver module modulates the first portion onto the correspondingsecond light beam, and (b) the module X/Y beam deflector of the firsttransceiver module deflects the modulated second light beam, carryingthe first portion, into the atmosphere in a first spatial direction; andwherein, during a second time period, (c) the module beam modulator ofthe first transceiver module modulates the second portion onto thecorresponding second light beam, and (d) the module X/Y beam deflectorof the first transceiver module deflects the modulated second lightbeam, carrying the second portion, into the atmosphere in a secondspatial direction.
 36. The optical router of claim 35, wherein the firstspatial direction corresponds to a first subscriber transceiver unitwhich receives the modulated second light beam; wherein the firstsubscriber transceiver unit transmits a third light beam carrying seconddata into the atmosphere; wherein, during the first time period, themodule X/Y beam deflector of the first transceiver module receives athird light beam from the atmosphere and deflects the third light beamto the module beam demodulator of the first transceiver module, and themodule beam demodulator demodulates the second data from the third lightbeam; wherein the module beam demodulator provides the second data tothe secondary transceiver unit through the electronic router; whereinthe secondary transceiver unit modulates the second data onto a fourthlight beam and transmits the modulated fourth light beam into theatmosphere.
 37. The optical router of claim 34, wherein the module beammodulator of a second transceiver module of said one or more transceivermodules is configured to receive a second of said portions of said firstdata from the electronic router, and modulate the second portion on thesecond light beam of the second transceiver module; wherein the moduleX/Y beam deflector in the second transceiver module is configured todeflect the modulated second light beam of the second transceiver moduleinto the atmosphere in a first spatial direction; wherein the modulebeam modulator of the second transceiver module is configured tomodulate the second portion of the first data on the second light beamof the second transceiver module while the module beam modulator of thefirst transceiver module modulates the one or more portions of the firstdata on the second light beam of the first transceiver module.
 38. Theoptical router of claim 34 further comprising a beam deflector controlsystem; wherein the first light beam includes control information;wherein the secondary transceiver unit is further configured todemodulate the control information from the first light beam; whereinthe secondary transceiver unit is configured to provide the controlinformation to the beam deflector control system through the electronicrouter; wherein the beam deflector control system is configured tocontrol the deflection orientation of the module X/Y beam deflector inthe first transceiver module in response to the control information. 39.The optical router of claim 38, wherein said control informationdetermines the one or more spatial directions in which the modulatedsecond light beam is deflected.
 40. The optical router of claim 38,wherein said beam deflector control system controls switching times ofthe module X/Y beam deflector in the first transceiver unit in responseto the control information.
 41. The optical router of claim 38, whereinsaid beam deflector control system is configured to control thedeflection orientation of the module X/Y beam deflector in each of theone or more transceiver modules in response to the control information.42. The optical router of claim 38, wherein the control informationcomprises beam stabilization information, wherein the beam stabilizationinformation indicates misalignment of the second light beam of the firsttransceiver module on a subscriber transceiver unit; wherein the beamdeflector control system is configured control an angular orientation ofthe module X/Y beam deflector of the first transceiver module so as tominimize the misalignment of the second light beam at the subscribertransceiver unit.
 43. The optical router of claim 34, wherein each ofsaid one or more transceiver modules further comprises a module beamdemodulator; wherein the module X/Y beam deflector of the firsttransceiver module is further configured to receive a third light beamcomprising second data from the atmosphere, and to deflect the thirdlight beam onto a optical path which targets the corresponding modulebeam demodulator; wherein the corresponding module beam demodulator isconfigured to demodulate the second data from the third light beam, andto provide the second data to the electronic router; wherein theelectronic router is configured to route the second data to thesecondary transceiver unit; wherein the secondary transceiver unit isconfigured to modulate the second data onto a fourth light beam, and totransmit the modulated fourth light beam into the atmosphere.
 44. Theoptical router of claim 43, wherein the secondary transceiver unitcomprises an optical antenna, a secondary light source and a secondarybeam modulator; wherein the secondary light source is configured togenerate the fourth light beam; wherein the secondary beam modulator isconfigured to receive the second data from the electronic router,modulate the second data onto the fourth light beam, and provide themodulated fourth light beam to the optical antenna; wherein the opticalantenna is configured to receive the modulated fourth light beam, andtransmit the modulated fourth light beam into the atmosphere.
 45. Theoptical router of claim 44, wherein the secondary transceiver unitfurther comprises an active optics control system and a secondary beamdemodulator; wherein the first light beam is transmitted into theatmosphere by a primary transceiver unit; wherein the first light beamfurther comprises beam stabilization information; wherein the secondarybeam demodulator is configured to receive the first light beam,demodulate the beam stabilization information and the first data fromthe first light beam; wherein the active optics control system isconfigured to receive the beam stabilization information, and adjust atransmission angle of the optical antenna so as to stabilize themodulated fourth light beam on a primary transceiver antenna of theprimary transceiver unit in response to the beam stabilizationinformation.
 46. The optical router of claim 45, wherein the secondarytransceiver unit further comprises a beam adjuster optically positionedbetween the optical antenna and the secondary beam modulator; whereinthe beam adjuster is configured to receive the modulated fourth lightbeam from the secondary beam modulator and to pass the modulated fourthlight beam to the optical antenna with an adjusted propagationdirection; wherein the active optics control system is furtherconfigured to control the beam adjuster to stabilize the modulatedfourth light beam on the primary transceiver antenna of the primarytransceiver unit.
 47. The optical router of claim 43, wherein the firstlight beam, received from the atmosphere by the secondary transceiverunit, is transmitted into the atmosphere by a primary transceiver; andwherein the secondary transceiver unit transmits the modulated fourthlight beam through the atmosphere to the primary transceiver.
 48. Theoptical router of claim 43, wherein the first transceiver module furthercomprises a module beam splitter optically positioned between the moduleX/Y beam deflector and the module beam modulator of the firsttransceiver module; wherein the module beam splitter is configured toreceive the third light beam from the module X/Y beam deflector, and toredirect a first portion of the third light beam to the module beamdemodulator; wherein the module beam demodulator is configured todemodulate the second data from the first portion of the third lightbeam.
 49. The optical router of claim 48, wherein the module beamsplitter of the first transceiver module is configured to receive themodulated second light beam from the module beam modulator of the firsttransceiver module, and to pass the modulated second light to the moduleX/Y beam deflector of the first transceiver module.
 50. The opticalrouter of claim 48, wherein the first transceiver module furthercomprises a module beam alignment detector; wherein the module beamsplitter is configured to redirect a second portion of the third lightbeam to the module beam alignment detector; wherein the module beamalignment detector is configured to detect misalignment of the thirdlight beam on the module X/Y beam deflector of the first transceivermodule based on the second portion of the third light beam, and generatecorresponding beam stabilization information; wherein the third lightbeam, received by the module X/Y beam deflector from the atmosphere, istransmitted into the atmosphere by a subscriber transceiver unit;wherein the beam stabilization information is usable by the subscribertransceiver unit to adjust a transmission angle of the third light beaminto the atmosphere so as to stabilize the third light beam on themodule X/Y beam deflector of the first transceiver module.
 51. Theoptical router of claim 50, wherein the module beam alignment detectoris further configured to provide the beam stabilization information tothe secondary transceiver unit via the electronic router; wherein thesecondary transceiver unit is configured to modulate the beamstabilization information in addition to the second data onto the fourthlight beam.
 52. The optical router of claim 34, wherein the secondarytransceiver unit further comprises an optical antenna and a secondarytransceiver beam demodulator; wherein the optical antenna is configuredto receive the first light beam from the atmosphere and to direct thefirst light beam onto an optical path which targets the secondarytransceiver beam demodulator; wherein the secondary transceiver beamdemodulator is configured to demodulate the first data from the firstlight beam, and provide the first data to the electronic router.
 53. Theoptical router of claim 52, wherein the optical antenna comprises amirror, wherein the mirror is configured to reflect the first light beamonto an optical path which targets the secondary transceiver beamdemodulator.
 54. The optical router of claim 53, wherein the opticalantenna further comprises a lens set which circumscribes said mirror;wherein said lens set is configured to receive the first light beam fromthe atmosphere and focus the first light beam on said mirror; andwherein said lens set has an aperture which admits passage of the firstlight beam after reflection from said mirror.
 55. The optical router ofclaim 54, wherein the lens set comprises an array of positive lenses.56. The optical router of claim 34, wherein the secondary transceiverunit further comprises an optical antenna and a secondary beam alignmentdetector; wherein the optical antenna is configured to receive the firstlight beam from the atmosphere; wherein the secondary beam alignmentdetector is configured to receive a first portion of the first lightbeam, detect misalignment of the first light beam on the optical antennabased on the first portion of the first light beam, and generate beamstabilization information; wherein the first light beam, received fromthe atmosphere by the optical antenna, is transmitted into theatmosphere by a primary transceiver unit, wherein the beam stabilizationinformation is usable by the primary transceiver unit to adjust atransmission angle of the first light beam so as to stabilize the firstlight beam on the optical antenna of the optical router.
 57. The opticalrouter of claim 56, wherein the secondary transceiver unit furthercomprises a secondary beam splitter; wherein the secondary beam splitteris configured to receive the first light beam from the optical antennaand redirect said first portion of the first light beam to the secondarybeam alignment detector.
 58. The optical router of claim 57, wherein thesecondary transceiver unit further comprises a secondary beamdemodulator; wherein the secondary beam splitter is further configuredto pass a second portion of the first light beam; wherein the secondarybeam demodulator is configured to receive the second portion of thefirst light beam, demodulate the first data from the second portion ofthe first light beam, and provide the first data to the electronicrouter.
 59. The optical router of claim 56, wherein the secondarytransceiver unit further comprises an active optics control system, asecondary light source and a secondary beam modulator, wherein thesecondary light source is configured to generate a fourth light beam;wherein the active optics control system is configured to provide thebeam stabilization information to the secondary beam modulator via theelectronic router; wherein the secondary beam modulator is configured tomodulate the beam stabilization information onto the fourth light beam,and direct the modulated fourth light beam to the optical antenna;wherein the optical antenna is configured to transmit the modulatedfourth light beam into the atmosphere to the primary transceiver unit.60. The optical router of claim 59, wherein the secondary transceiverunit further comprises a secondary beam demodulator and a secondary beamadjuster; wherein the secondary beam adjuster is configured to receivethe first light beam from the optical antenna and to change a directionof travel of the first light beam; wherein the active optics controlsystem is further configured to control the beam adjuster so as tooptimize an amount of the first light beam arriving at the secondarybeam demodulator in response to the beam stabilization information. 61.The optical router of claim 34, wherein the one or more transceivermodules are arrayed in a circular configuration to provide a 360 degreerange of coverage for atmospheric optical communication withsubscribers.
 62. The optical router of claim 34, wherein the one or moretransceiver modules are configured to couple to a circular backplane,wherein the electronic router is also configured to couple to thecircular backplane.
 63. An optical router comprising: an optical antennaconfigured to receive a first light beam comprising first data from theatmosphere; a secondary transceiver beam demodulator configured toreceive the first light beam from the optical antenna and demodulate thefirst data from the first light beam; one or more transceiver modules,wherein each of said one or more transceiver modules comprises a modulelight source, configured to generate a corresponding second light beam,a module beam modulator and a module X/Y beam deflector; an electronicrouter configured to receive the first data from the secondarytransceiver beam demodulator and to transmit at least a first portion ofthe first data to a first transceiver module of said one or moretransceiver modules; wherein the module beam modulator of said firsttransceiver module is configured to modulate said at least the firstportion of the first data onto the corresponding second light beam,wherein the module X/Y beam deflector is configured to receive themodulated second light beam and to deflect the modulated second lightbeam into the atmosphere in a first controllable direction.
 64. Theoptical router of claim 63 further comprising a secondary transceiverbeam modulator; wherein each of said one or more transceiver modulesfurther comprises a module beam demodulator; wherein the module X/Y beamdeflector of the first transceiver module is further configured toreceive a third light beam comprising second data from the atmosphere,and to deflect the third light beam to the corresponding module beamdemodulator; wherein the corresponding module beam demodulator isconfigured to demodulate the second data from the third light beam, andto provide the second data to the electronic router; wherein theelectronic router is configured to provide the second data to thesecondary transceiver beam modulator; wherein the secondary transceiverbeam modulator is configured to modulate the second data onto a fourthlight beam; wherein the optical antenna is configured to transmit themodulated fourth light beam into the atmosphere.